Oh you want to know tire pressure. My personal thoughts, the carcasses of these heavier rated tires will probably hold up to a variaty of pressures. I personally like the 20-25 range and ususally don't air them up much more unless I'm on a long stretch (500 miles) of pavement.

Depends on how fast you are going how far, how loaded the bike is, if there is the slightest chance of an imbeded hard edge or jump AND you don't like replacing your wheels, how good of fuel economy and range you want, and how much the bike deflecting some bothers you.

20 in the back and 15 in the front does FEEL better on a moderatly loaded bike, but a hard edge or jump can destroy your wheel at this pressure. Also heat build up in the tire on gravel is no different then on the road, if your going far fast you may not get away with it

I started h/s gravel doing 30 MPH on tires aired down to 20 PSI. I now do gravel at up to 80 MPH aired up to 42 PSI.